TWI816312B - Charged particle beam irradiation system - Google Patents

Abstract

[Problem] Provide a charged particle beam irradiation system that can appropriately irradiate a subject with a charged particle beam. [Solution] By adjusting the penumbra of the charged particle beam (B) with the snorkel deenergizer (30), it is possible to suppress the irradiation of the tumor (14) when the irradiation part (2) irradiates near the boundary of the tumor (14). ) externally irradiated charged particle beam (B). Here, the holding part (60) holding the snorkel deenergizer (30) is provided in the irradiation part (2). Therefore, positional alignment between the charged particle beam (B) irradiated onto the tumor (14) and the ventilator deenergizer (30) can be easily performed. Therefore, the irradiation unit (2) can irradiate the tumor (14) with the charged particle beam (B) in a state where the penumbra is adjusted to an appropriate position using the ventilator deenergizer (30). In this embodiment, it is only necessary to hold the snorkel deenergizer (30) on the holding portion (60), so positioning is easy.

Description

Charged particle beam irradiation system

The invention relates to a charged particle beam irradiation system. This application claims priority based on Japanese Patent Application No. 2021-033429 filed on March 3, 2021. The entire contents of this Japanese application are incorporated by reference into this specification.

Conventionally, as a charged particle beam irradiation system that performs treatment by irradiating a charged particle beam to an affected part of a patient, for example, the device described in Patent Document 1 is widely known. In the charged particle beam irradiation system described in Patent Document 1, the irradiation unit irradiates the charged particle beam in a scanning manner. That is, the irradiation unit performs irradiation while moving the irradiation position of the affected area with the charged particle beam by scanning with the scanning electromagnet. [Prior technical literature]

[Patent Document 1] Japanese Patent Application Publication No. 2017-209372

[Problem to be solved by the invention]

Here, there is a problem that when the irradiation unit irradiates the charged particle beam in a scanning manner, the treatment dose is applied to the outside of the irradiated object due to the large beam size of the charged particle beam or the like. Therefore, it is required to appropriately irradiate the irradiated object with the charged particle beam.

Therefore, an object of the present invention is to provide a charged particle beam irradiation system capable of appropriately irradiating a subject to be irradiated with a charged particle beam. [Technical means to solve problems]

In order to solve the above problem, a charged particle beam irradiation system of the present invention irradiates a charged particle beam to an irradiated object in a target object. The charged particle beam irradiation system includes an irradiation unit that scans the charged particle beam with a scanning electromagnet. The irradiated object is irradiated with a charged particle beam; the adjustment member adjusts the penumbra of the scanned charged particle beam; and the holding part is provided on the irradiation part and holds the adjustment member.

The charged particle beam irradiation system of the present invention includes: an irradiation unit that irradiates the irradiated object with the charged particle beam by scanning the charged particle beam with a scanning electromagnet; and an adjustment member that adjusts the penumbra of the charged particle beam. Therefore, by adjusting the penumbra of the charged particle beam by the adjusting member, it is possible to suppress the charged particle beam from being irradiated to the outside of the irradiated object when the irradiating unit irradiates the vicinity of the boundary portion of the irradiated object. Here, the holding part holding the adjustment member is provided in the irradiation part. Therefore, the irradiation unit can irradiate the irradiated object with the charged particle beam in a state where the penumbra is adjusted to an appropriate position using the adjustment member. Based on the above, the irradiation unit can appropriately irradiate the irradiated object with the charged particle beam.

The holding part may be provided at the front end of the irradiation part. At this time, the adjusting member can adjust the penumbra at a position close to the object. Therefore, after the penumbra is adjusted by the adjusting member, the charged particle beam is quickly irradiated to the irradiated object before the beam spread becomes large.

The adjustment member may have an adjustment level of the penumbra corresponding to the depth of the irradiated object within the object. At this time, the adjustment member can adjust the penumbra at an adjustment level corresponding to the depth of the irradiated object within the object.

The charged particle beam irradiation system may be configured to be able to select the adjustment level of the penumbra of the adjustment member in accordance with the depth of the irradiated object within the object. At this time, the adjustment member can adjust the penumbra with an appropriate adjustment level of the penumbra according to the depth of the irradiated object within the object.

The charged particle beam irradiation system may be configured to be able to select the adjustment level of the penumbra of the adjustment member in accordance with the distance between the object and the irradiation part. At this time, the adjustment member can adjust the penumbra with an appropriate adjustment level of the penumbra according to the distance between the object and the irradiation part.

The charged particle beam irradiation system may further include a detection unit that detects that the adjustment member is incorrectly arranged with respect to the holding unit. In this case, it is possible to suppress adjustment of the penumbra by an adjustment member of an inappropriate adjustment level. [Effects of the invention]

According to the present invention, it is possible to provide a charged particle beam irradiation system capable of appropriately irradiating a subject to be irradiated with a charged particle beam.

Hereinafter, a charged particle beam irradiation system according to an embodiment of the present invention will be described with reference to the drawings. In addition, in the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted.

FIG. 1 is a schematic structural diagram showing a charged particle beam irradiation system 1 according to an embodiment of the present invention. The charged particle beam irradiation system 1 is a system used for cancer treatment based on radiotherapy and the like. The charged particle beam irradiation system 1 includes: an accelerator 3 that accelerates charged particles generated by an ion source device and emits them as a charged particle beam; an irradiation unit 2 that irradiates a charged particle beam to an irradiated object; and a beam transport path 21 that irradiates the charged particle beam from the accelerator. The charged particle beam emitted from 3 is transported to the irradiation part 2. The irradiation unit 2 is installed on a rotating bracket 5 arranged around the treatment table 4 . The irradiation unit 2 can rotate around the treatment table 4 via the rotating bracket 5 . In addition, further detailed structures of the accelerator 3, the irradiation unit 2, and the beam transport path 21 will be described later.

FIG. 2 is a schematic structural diagram of the vicinity of the irradiation unit 2 of the charged particle beam irradiation system 1 of FIG. 1 . In addition, in the following description, the terms "X-axis direction", "Y-axis direction", and "Z-axis direction" are used for description. The “Z-axis direction” refers to the direction in which the basic axis AX of the charged particle beam B extends, and is the depth direction of the irradiation of the charged particle beam B. In addition, the “basic axis AX” is the irradiation axis of the charged particle beam B when it is not deflected by the scanning electromagnet 50 to be described later. FIG. 2 shows a state in which the charged particle beam B is irradiated along the basic axis AX. "X-axis direction" refers to a direction in a plane orthogonal to the Z-axis direction. "Y-axis direction" refers to the direction orthogonal to the X-axis direction in a plane orthogonal to the Z-axis direction.

First, the schematic structure of the charged particle beam irradiation system 1 of this embodiment will be described with reference to FIG. 2 . The charged particle beam irradiation system 1 is an irradiation device related to the scanning method. In addition, the scanning method is not particularly limited, and line scanning, raster scanning, point scanning, etc. can be used. As shown in FIG. 2 , the charged particle beam irradiation system 1 includes an accelerator 3 , an irradiation unit 2 , a beam transport path 21 , a control unit 7 , a treatment planning device 90 and a memory unit 95 .

The accelerator 3 is a device that accelerates charged particles and emits a charged particle beam B with a preset energy. Examples of the accelerator 3 include a cyclotron, a synchrocyclotron, and a linear accelerator. When the accelerator 3 is a cyclotron that emits a charged particle beam B with a predetermined energy, the energy of the charged particle beam sent to the irradiation unit 2 can be adjusted (lowered) by using an energy adjustment unit. The accelerator 3 is connected to the control unit 7 and can control the supplied current. The charged particle beam B generated by the accelerator 3 is transported to the irradiation part 2 through the beam transport path 21 . The beam transport path 21 connects the accelerator 3 and the irradiation part 2, and transports the charged particle beam emitted from the accelerator 3 to the irradiation part 2.

The beam transport path 21 has an energy adjustment device (ESS: Energy Selection System) that adjusts the energy of the charged particle beam B while transporting it. Among them, the beam delivery path 21 has an energy reducer 20 near the exit of the accelerator 3 . The energy reducer 20 is a member that adjusts the range of the charged particle beam B and adjusts the reaching depth of the charged particle beam B in the body of the patient 15 (object). The energy reducer 20 adjusts the range by consuming the energy of the charged particle beam B. The energy reducer 20 can adjust the range of the charged particle beam B by adjusting the thickness of the part through which the charged particle beam B passes. In addition, the ESS suppresses energy fluctuations or beam size expansion (using a collimator) occurring in the beam delivery path downstream of the ESS, in addition to energy loss in the energy reducer 20 . The energy reducer 20 is made of materials such as beryllium and carbon, for example. The energy reducer 20 is disposed at a position on the upstream side (that is, on the accelerator 3 side) in the traveling direction of the charged particle beam B in the beam transport path 21 . In the example shown in FIG. 1 , the energy reducer 20 is disposed immediately behind the accelerator 3 in the path upstream of the rotation bracket 5 , that is, at the closest position among the electromagnets and other equipment of the beam transport path 21 . Upstream side. However, the position of the energy reducer 20 within the beam delivery path 21 is not particularly limited.

The irradiation unit 2 irradiates the charged particle beam B to the tumor (irradiation subject) 14 in the body of the patient 15 (object). The charged particle beam B refers to high-speed accelerated charged particles, and examples thereof include proton beams, heavy particle (heavy ion) beams, and electron beams. Specifically, the irradiation unit 2 is a device that irradiates the tumor 14 with the charged particle beam B emitted from the accelerator 3 that accelerates charged particles generated by an ion source (not shown) and transported through the beam transport path 21 . The irradiation unit 2 includes a scanning electromagnet 50, a four-pole electromagnet 8, a cross-section monitor 11, a dose monitor 12, position monitors 13a and 13b, a collimator 40, and a vent tube deenergizer 30 (adjustment member). The scanning electromagnet 50, each of the monitors 11, 12, 13a, and 13b, the four-pole electromagnet 8, and the snorkel deenergizer 30 are accommodated in the irradiation nozzle 9 as a storage body. In this manner, the irradiation section 2 is configured by accommodating each main component in the irradiation nozzle 9 . In addition, the four-pole electromagnet 8, the profile monitor 11, the dose monitor 12 and the position monitors 13a and 13b can be omitted.

As the scanning electromagnet 50, the X-axis direction scanning electromagnet 50A and the Y-axis direction scanning electromagnet 50B are used. The X-axis direction scanning electromagnet 50A and the Y-axis direction scanning electromagnet 50B are each composed of a pair of electromagnets. The magnetic field between the pair of electromagnets is changed according to the current supplied from the control unit 7, and the magnetic field between the pair of electromagnets is scanned. The charged particle beam B. The X-axis direction scanning electromagnet 50A scans the charged particle beam B in the X-axis direction, and the Y-axis direction scanning electromagnet 50B scans the charged particle beam B in the Y-axis direction. The scanning electromagnets 50 are sequentially arranged on the base axis AX and on the downstream side of the charged particle beam B than the accelerator 3 . In addition, the scanning electromagnet 50 scans the charged particle beam B so as to irradiate the charged particle beam B in a scanning pattern pre-planned by the treatment planning device 90 . How to control the scanning electromagnet 50 will be described later.

The four-pole electromagnet 8 includes an X-axis direction four-pole electromagnet 8a and a Y-axis direction four-pole electromagnet 8b. The X-axis direction quadrupole electromagnet 8 a and the Y-axis direction quadrupole electromagnet 8 b shrink and converge the charged particle beam B according to the current supplied from the control unit 7 . The X-axis direction quadrupole electromagnet 8a converges the charged particle beam B in the X-axis direction, and the Y-axis direction quadrupole electromagnet 8b converges the charged particle beam B in the Y-axis direction. By changing the current supplied to the quadrupole electromagnet 8 to change the reduction amount (convergence amount), the beam size of the charged particle beam B can be changed. The four-pole electromagnets 8 are sequentially arranged on the base axis AX and between the accelerator 3 and the scanning electromagnet 50 . In addition, the beam size refers to the size of the charged particle beam B on the XY plane. In addition, the beam shape refers to the shape of the charged particle beam B on the XY plane.

For positioning during initial setting, the profile monitor 11 detects the beam shape and position of the charged particle beam B. The profile monitor 11 is arranged on the base axis AX between the four-pole electromagnet 8 and the scanning electromagnet 50 . The dose monitor 12 detects the dose of the charged particle beam B. The dose monitor 12 is arranged on the base axis AX and relative to the downstream side of the scanning electromagnet 50 . The position monitors 13a and 13b detect and monitor the beam shape and position of the charged particle beam B. The position monitors 13 a and 13 b are arranged on the base axis AX and on the downstream side of the charged particle beam B than the dose monitor 12 . Each of the monitors 11, 12, 13a, and 13b outputs the detection result to the control unit 7.

The collimator 40 is provided at least on the downstream side of the charged particle beam B than the scanning electromagnet 50 , and is a member that shields a part of the charged particle beam B and allows a part to pass therethrough. Here, the collimator 40 is provided on the downstream side of the position monitors 13a and 13b. The collimator 40 is connected to a collimator driving unit 51 that moves the collimator 40 .

The snorkel deenergizer 30 reduces the energy of the charged particle beam B passing through to adjust the energy of the charged particle beam B. The snorkel deenergizer 30 is configured as an adjustment member for adjusting the penumbra of the charged particle beam B. In this embodiment, the snorkel deenergizer 30 is held by the holding portion 60 provided at the front end portion 9 a of the irradiation nozzle 9 . In addition, the front end portion 9a of the irradiation nozzle 9 refers to the end portion of the charged particle beam B on the downstream side. Detailed description of the snorkel deenergizer 30 and the holding part 60 will be described later.

The control unit 7 is composed of, for example, a CPU, ROM, RAM, and the like. The control unit 7 controls the accelerator 3, the thickness adjustment mechanism of the energy reducer 20, the scanning electromagnet 50, the four-pole electromagnet 8, and the collimator driving unit based on the detection results output from the respective monitors 11, 12, 13a, and 13b. 51.

Furthermore, the control unit 7 of the charged particle beam irradiation system 1 is connected to a treatment planning device 90 that performs a treatment plan for charged particle beam treatment and a memory unit 95 that stores various data. The treatment planning device 90 measures the tumor 14 of the patient 15 by CT or the like before treatment, and plans the dose distribution (dose distribution of the charged particle beam to be irradiated) at each position of the tumor 14 . Specifically, the treatment planning device 90 creates a scan pattern for the tumor 14 . The treatment planning device 90 sends the created scan pattern to the control unit 7 . In the scanning pattern created by the treatment planning device 90, it is planned to draw what scanning path the charged particle beam B draws at what scanning speed.

When irradiating a charged particle beam by a scanning method, the tumor 14 is virtually divided into a plurality of layers in the Z-axis direction, and each layer is scanned in such a manner that the charged particle beam follows the scanning path determined in the treatment plan. and illuminate. Then, after the irradiation of the charged particle beam in this layer is completed, the irradiation of the charged particle beam B in the adjacent layer is performed.

In the case where the charged particle beam irradiation system 1 shown in FIG. 2 is irradiating the charged particle beam B by the scanning method, the quadrupole electromagnet 8 is set to the operating state (open), so that the charged particles passing through Beam B converges.

Next, the charged particle beam B is emitted from the accelerator 3 . The ejected charged particle beam B is scanned in accordance with the scanning pattern determined in the treatment plan through the control of the scanning electromagnet 50 . Thereby, the charged particle beam B is irradiated while scanning the irradiation range in one layer set in the Z-axis direction. After the irradiation of one layer is completed, the charged particle beam B is irradiated to the next layer.

Referring to FIGS. 3(a) and 3(b) , a charged particle beam irradiation image of the scanning electromagnet 50 corresponding to the control of the control unit 7 will be described. FIG. 3(a) shows an irradiated object virtually cut into a plurality of layers in the depth direction, and FIG. 3(b) shows a scanned image of a charged particle beam in one layer viewed from the depth direction.

As shown in Figure 3(a), the irradiated object is virtually cut into a plurality of layers in the depth direction of the irradiation. In this example, the layer is virtually cut into layers L ₁ in order from the deep layer (where the charged particle beam B has a long range). , layer L ₂ , ... layer L _n-1 , layer L _n , layer L _n+1 , ... layer L _N-1 , layer L _{N and} these N layers. Furthermore, as shown in FIG. 3(b) , regarding the charged particle beam B, while drawing the beam trajectory along the scanning path TL, in the case of continuous irradiation (line scanning or raster scanning), the beam path along the layer L _n The scanning path TL is continuously irradiated, and in the case of point scanning, a plurality of irradiation points of the layer _Ln are irradiated on one side. The charged particle beam B is irradiated along the scanning path TL1 extending in the X-axis direction, slightly displaced in the Y-axis direction along the scanning path TL2, and irradiated along the adjacent scanning path TL1. In this way, the charged particle beam B emitted from the irradiation part 2 controlled by the control part 7 moves on the scanning path TL.

Next, referring to FIGS. 4 to 7 , the snorkel deenergizer 30 will be described in detail. FIG. 4 is a schematic diagram showing the state in which the snorkel deenergizer 30 is held by the holding part 60. As shown in FIG. 4 , as an example, the snorkel deenergizer 30 is a member having a rectangular plate shape. The snorkel deenergizer 30 has a planar incident surface 30a and an exit surface 30b extending in a direction orthogonal to the base axis AX. Since the snorkel deenergizer 30 has a uniform thickness within the range scanned by the charged particle beam B, it will attenuate a certain amount of energy. The snorkel deenergizer 30 can change the energy adjustment amount of the charged particle beam B by changing the thickness, that is, the size between the incident surface 30a and the exit surface 30b. Thereby, the snorkel deenergizer 30 can adjust the penumbra of the charged particle beam B by adjusting the expansion of the beam size of the charged particle beam B. The snorkel deenergizer 30 is made of, for example, polyethylene, acrylic, or other materials with a density close to water. In addition, the snorkel deenergizer 30 has the purpose of adjusting the spread of the charged particle beam B.

The holding part 60 is provided in the irradiation part 2 and holds the snorkel deenergizer 30 on the irradiation part 2 side. Since the holding portion 60 is provided at the front end portion 9 a of the irradiation nozzle 9 , the ventilator deenergizer 30 is disposed downstream of all components disposed inside the irradiation nozzle 9 , that is, closer to the patient 15 . By being held by the holding part 60 , the snorkel deenergizer 30 is installed on the irradiation part 2 side. The state provided on the side of the irradiation unit 2 is, for example, a state in which the ventilator deenergizer 30 is movable as the irradiation unit 2 moves. This does not mean that the ventilator deenergizer 30 is disposed around the patient 15, or that the ventilator deenergizer 30 is disposed around the patient 15. Patient 15 is in a state where a ventilator is installed on the hospital bed. The holding part 60 can hold the ventilator deenergizer 30 on the irradiation part 2 side and also hold the ventilator deenergizer 30 at the position closest to the patient 15 . In addition, the position closest to the patient 15 means that the position of the patient 15 and the ventilator deenergizer 30 is, for example, closer than 30 cm. However, the distance between the ventilator deenergizer 30 and the patient 15 can be appropriately changed depending on the relationship with the surrounding environment and the like.

The holding part 60 has a pair of side wall parts 61 that support the outer peripheral edge part 30 c of the snorkel deenergizer 30 . The holding part 60 has a pair of side wall parts 62 opposed to the other outer peripheral edge part 30c (see FIG. 4(b) ). The side wall portions 61 and 62 extend downward from the support portion 86 . A wide member 87 is provided at the front end portions of the side wall portions 61 and 62 . In addition, the holding part 60 can hold the snorkel deenergizer 30 of a plurality of thicknesses. For example, the holding portion 60 can hold the thin snorkel deenergizer 30A and can also hold the thick snorkel deenergizer 30B. When changing the thickness, the user takes out the thin snorkel deenergizer 30A from the holding part 60 and holds the thick snorkel deenergizer 30B in the holding part 60 . As described above, since the holding portion 60 is configured to be able to hold a snorkel deenergizer having a plurality of thicknesses, it can be said to have a structure that allows the adjustment level of the penumbra to be selected, that is, the thickness. In addition, the holding part 60 may also serve as a filler holder used in the swing irradiation method, for example. Therefore, the holding portion 60 can hold the snorkel deenergizer 30 via the filler holder 66 . Furthermore, the holding part 60 may have a collimator holder 67 for holding the collimator on the lower side of the filler holder 66.

Here, the penumbra will be described with reference to FIG. 5 . FIG. 5 is a graph showing the dose distribution when the charged particle beam B is irradiated in a predetermined plane in which the scanning normal direction is at right angles to the base axis AX. The horizontal axis represents the position in the predetermined direction of the predetermined plane, and the vertical axis represents the dose at each position. However, in order to facilitate understanding, the graph shown in FIG. 5 is modified and shown. The graph G1 in FIG. 5 shows the dose distribution of the charged particle beam B per pass. By scanning the charged particle beam B in a predetermined plane, a plurality of graphs G1 are formed in a gradually shifted state at each position. The total dose distribution by superimposing these graphs G1 is represented by graph G2. The area indicated by W in FIG. 5 represents the base condition target width. The reference condition target width W represents the width of the irradiated object as the irradiation target in a plane. The width of the tumor 14 within the irradiation plane serves as the reference condition target width W. Within the range of the reference condition target width W, the graph G2 forms a flat area FE. The flat area FE is an area where the dose is approximately uniform and the difference in dose falls within a predetermined range. On the other hand, the area outside the reference condition target width W becomes the penumbra P.

Here, the snorkel deenergizer 30 can suppress the expansion of the beam size of the charged particle beam B. Therefore, in the case of suppressing the penumbra, the snorkel deenergizer 30 reduces the spread of the charged particle beam B (see diagram G1a). As a result, the dose distribution changes as a whole and the spread of the charged particle beam B becomes smaller, thereby suppressing the penumbra P (see graph G2a).

FIG. 6 is a graph showing simulation results related to the relationship between the spread of the charged particle beam B and the depth of the target object. The graph shown in FIG. 6 shows the charged particle beam B when the snorkel deenergizer 30 is set to an arbitrary thickness and the charged particle beam B is irradiated into the water using Monte Carlo simulation experiment calculation at each thickness. Diagram of expansion in water. The horizontal axis represents the distance from the surface of the water tank. This corresponds to the depth of the tumor 14 from the surface of the patient's 15 body. The vertical axis represents the expansion of the charged particle beam B. The expansion is a value calculated by Gaussian fitting. In addition, in FIG. 6 , the distance between the snorkel deenergizer 30 and the water tank, that is, the thickness of the air layer through which the charged particle beam B emitted from the snorkel deenergizer 30 passes is set to 50 mm. This corresponds to the distance between the ventilator deenergizer 30 and the surface of the patient's 15 body.

As shown in FIG. 6 , at shallow locations, the greater the thickness of the snorkel deenergizer 30 , the more it can suppress the expansion of the charged particle beam B. On the other hand, in a deep location, the thinner the thickness of the snorkel deenergizer 30 is, the more it can suppress the expansion of the charged particle beam B. Based on such simulation results, the charged particle beam irradiation system 1 can be configured to select the adjustment level (thickness here) of the penumbra of the ventilator deenergizer 30 according to the depth of the tumor 14 in the patient 15 .

For example, in the case where the tumor 14 exists in a shallow part E1a (less than 10 cm) in the body, the ventilation tube deenergizer 30 with a thickness of 13 cm may be selected. In addition, when the tumor 14 exists in the deep part E2a (10 cm or more) in the body, the ventilation tube deenergizer 30 with a thickness of 0 cm or a thickness of 4 cm can be selected. Alternatively, in the case where the tumor 14 exists in a shallow part E1b (less than 7 cm) in the body, the ventilation tube deenergizer 30 with a thickness of 12 cm may be selected. In addition, when the tumor 14 exists in the middle part E2b (7 cm or more and less than 12 cm) in the body, the ventilation tube deenergizer 30 with a thickness of 8 cm can be selected. In addition, when the tumor 14 exists in the deep part E3b (more than 12 cm) in the body, the ventilation tube deenergizer 30 with a thickness of 0 cm or a thickness of 4 cm can be selected.

7 and 8 are graphs showing simulation results when the thickness of the air layer is changed based on FIG. 6 . FIG. 7 shows the simulation results when the thickness of the air layer is 100 mm, and FIG. 8 shows the simulation results when the thickness of the air layer is 200 mm. As shown in FIGS. 6 to 8 , the relationship between the depth of the snorkel deenergizer 30 and the spread of the charged particle beam B changes depending on the thickness of the air layer. Therefore, the charged particle beam irradiation system 1 may be configured to be able to select the adjustment level (that is, the thickness) of the penumbra of the ventilator deenergizer 30 according to the distance between the patient 15 and the irradiation part 2 (see FIG. 2 ).

Next, referring to FIG. 4 and FIG. 9 , a structure that enables selection of the adjustment level (ie, thickness) of the penumbra of the snorkel deenergizer 30 will be described. FIG. 9 is a block diagram showing a structure for enabling selection of the adjustment level of the penumbra of the snorkel deenergizer 30 . As shown in FIG. 9 , the charged particle beam irradiation system 1 includes the aforementioned control unit 7 , output unit 76 , reading unit 77 , and identification information detection unit 78 . Furthermore, the control unit 7 includes an information acquisition unit 70 , a calculation unit 71 , and a determination unit 72 .

The information acquisition unit 70 acquires various information regarding the irradiation of the charged particle beam B from the treatment planning device 90 and the memory unit 95 . The information acquisition unit 70 can acquire information on the depth of the tumor 14 in the patient 15 and information on the distance between the patient 15 and the irradiation unit 2 (see FIG. 2 ) from the treatment plan created by the treatment planning device 90 . The calculation unit 71 performs various calculations related to the selection of the adjustment level of the penumbra of the snorkel deenergizer 30 . The calculation unit 71 selects the adjustment level of the penumbra of the ventilator deenergizer 30 based on at least one of the information on the depth of the tumor 14 in the patient 15 and the information on the distance between the patient 15 and the irradiation unit 2 (see FIG. 2 ). That is, thickness. For example, the calculation unit 71 may select the thickness of the snorkel deenergizer 30 by comparing the previously prepared data and the acquired information as shown in FIGS. 6 to 8 . Alternatively, the calculation unit 71 may select an appropriate thickness of the snorkel deenergizer 30 by performing calculations based on the acquired information. However, the treatment planning device 90 may select an appropriate thickness of the ventilator deenergizer 30 , and at this time, the information acquisition unit 70 acquires information on the thickness of the ventilator deenergizer 30 . The determination unit 72 determines whether the correct snorkel deenergizer 30 is arranged in the holding unit 60 .

The output unit 76 outputs various information. The output unit 76 is composed of a monitor, a speaker, and the like. For example, the output unit 76 may output information about the thickness of the selected snorkel deenergizer 30 to the user. Thereby, the user can arrange the snorkel deenergizer 30 with the thickness selected by the control part 7 on the holding part 60 .

Here, the reading unit 77 , the identification information detection unit 78 and the determination unit 72 are configured as the detection unit 80 which detects that the snorkel deenergizer 30 is incorrectly arranged with respect to the holding unit 60 .

Specifically, the reading unit 77 reads information on the thickness from the thickness information holding unit 81 (see FIG. 4(a) ) given to each snorkel deenergizer 30 . The thickness information holding unit 81 is not particularly limited as long as it can hold information related to thickness, and may be composed of a barcode, for example. At this time, the reading unit 77 is constituted by a barcode reader. Furthermore, the thickness information holding unit 81 may be formed of a QR code (registered trademark), and the reading unit 77 may be formed of a QR code reader. The thickness information holding unit 81 may be formed of a magnetic information holding mechanism, and the reading unit 77 may also be formed. It consists of a device that reads the magnetic information.

The identification information detection unit 78 detects information capable of identifying the snorkel deenergizer 30 held by the holding unit 60 . For example, the identification information detection unit 78 may detect a signal from a predetermined detection mechanism provided in the holding unit 60 as the identification information. When the snorkel de-energizer 30 is held by the holding part 60, such a detection mechanism can send a signal indicating the thickness of the held snorkel de-energizer 30 to the identification information detection part 78.

The determination unit 72 determines whether the thickness selected by the calculation unit 71 and the thickness read by the reading unit 77 match. In the case of inconsistency, the determination unit 72 outputs information on the situation in which the wrong snorkel deenergizer 30 is arranged through the output unit 76 . If they match, the determination unit 72 outputs information about the correct arrangement of the snorkel deenergizer 30 through the output unit 76 .

The determination unit 72 compares the thickness information read by the reading unit 77 with the thickness selected by the calculation unit 71 . At this time, the user can determine the error in advance by reading the thickness information from the reading unit 77 before the snorkel deenergizer 30 is arranged on the holding unit 60 . Furthermore, the determination unit 72 determines the thickness of the snorkel deenergizer 30 held by the holding unit 60 based on the identification information detected by the identification information detection unit 78, and compares the thickness with the thickness selected by the calculation unit 71. At this time, the user can determine the error without performing a reading operation by the reading unit 77 .

Next, the charged particle beam irradiation method of this embodiment will be described with reference to FIG. 10 . FIG. 10 is a step diagram showing the contents of the charged particle beam irradiation method of this embodiment. As shown in FIG. 10 , the adjustment level (that is, the thickness) of the penumbra of the ventilator deenergizer 30 is selected based on at least one of the depth of the tumor 14 in the body of the patient 15 and the distance between the patient 15 and the irradiation unit 2 . Step S10. Next, step S20 is executed in which the snorkel deenergizer 30 selected in step S10 is arranged in the holding portion 60 . Next, step S30 is executed in which the detection unit 80 (see FIG. 9 ) is used to determine whether the incorrect snorkel deenergizer 30 is arranged in the holding unit 60 . In addition, when the reading unit 77 is used, step S30 of determination is executed before step S20. Next, if the correct ventilator deenergizer 30 is arranged, step S40 in which the irradiation unit 2 irradiates the charged particle beam B to the tumor 14 is executed.

Next, the functions/effects of the charged particle beam irradiation system 1 and the charged particle beam irradiation method of this embodiment will be described.

The charged particle beam irradiation system 1 of this embodiment includes: an irradiation unit 2 that irradiates the tumor 14 with the charged particle beam B by scanning the charged particle beam B with the scanning electromagnet 50; and a ventilator deenergizer 30 that adjusts the charged particle beam. Penumbra of B. Therefore, by adjusting the penumbra of the charged particle beam B by the ventilator deenergizer 30, it is possible to suppress the charged particle beam B from being irradiated to the outside of the tumor 14 when the irradiation unit 2 irradiates the vicinity of the boundary of the tumor 14. Here, the holding part 60 holding the snorkel deenergizer 30 is provided in the irradiation part 2 . Therefore, positional alignment between the charged particle beam B irradiated onto the tumor 14 and the ventilator deenergizer 30 can be easily performed. Therefore, the irradiation unit 2 can irradiate the tumor 14 with the charged particle beam B in a state where the penumbra is adjusted to an appropriate position using the ventilator deenergizer 30 . For example, when a ventilator deenergizer is installed on the bed side of the patient 15, the staff must position the ventilator deenergizer while considering the positional relationship between the patient 15 and the irradiation unit 2. However, it is difficult to see the ventilator deenergizer because it is difficult for the patient 15 to see it. , so there is a problem of difficulty in position alignment. On the other hand, in this embodiment, it is only necessary to hold the snorkel deenergizer 30 on the holding part 60, so positioning is easy. Based on the above, the irradiation unit 2 can appropriately irradiate the tumor 14 with the charged particle beam B.

The holding part 60 may be provided at the front end part 9a of the irradiation part 2. At this time, the ventilator deenergizer 30 can adjust the penumbra at a position close to the patient 15 . Therefore, after the ventilator deenergizer 30 adjusts the penumbra, the charged particle beam B is quickly irradiated to the tumor 14 before it expands and becomes larger.

The charged particle beam irradiation system 1 may be configured to be able to select the adjustment level of the penumbra of the ventilator deenergizer 30 according to the depth of the tumor 14 in the body of the patient 15 . At this time, the ventilator deenergizer 30 can adjust the penumbra with an appropriate penumbra adjustment level according to the depth of the tumor 14 in the body of the patient 15 .

The charged particle beam irradiation system 1 may be configured to be able to select the adjustment level of the penumbra of the ventilator deenergizer 30 depending on the distance between the patient 15 and the irradiation unit 2 . At this time, the ventilator deenergizer 30 can adjust the penumbra with an appropriate penumbra adjustment level according to the distance between the patient 15 and the irradiation part 2 .

The charged particle beam irradiation system 1 may further include a detection unit 80 that detects that the snorkel deenergizer 30 is incorrectly arranged with respect to the holding unit 60 . At this time, it is possible to suppress the adjustment of the penumbra by the snorkel deenergizer 30 with an inappropriate adjustment level.

The charged particle beam irradiation method of this embodiment is a charged particle beam irradiation method of irradiating the charged particle beam B to the tumor 14 in the patient 15's body. The charged particle beam irradiation method includes: step S10, based on the characteristics of the tumor 14 in the patient 15's body. depth to select the adjustment level of the penumbra of the ventilator deenergizer 30 that adjusts the penumbra of the charged particle beam B; step S20, configure the selected ventilator deenergizer 30 relative to the charged particle beam B; and step S40, The tumor 14 is irradiated with the charged particle beam B by scanning the charged particle beam B with the scanning electromagnet 50 .

According to this charged particle beam irradiation method, the ventilator deenergizer 30 can adjust the penumbra at an appropriate penumbra adjustment level according to the depth of the tumor 14 in the patient 15 . Based on the above, the tumor 14 can be appropriately irradiated with the charged particle beam B.

In large hospitals with a large number of patients, when treating cases (such as head and neck cases) that usually use low-energy proton beams, in the treatment using an adjustment member (ventilator deenergizer) as in this embodiment, the beam is used Efficiency becomes good. Since the amount of proton beam used is limited for each facility, if the efficiency is high, the number of patients to be treated can be increased compared to conventional control under ESS.

The ventilator deenergizer 30 may have an adjustment level corresponding to the distance between the patient 15 and the irradiation part 2 . At this time, the ventilator deenergizer 30 can adjust the penumbra at an adjustment level corresponding to the distance between the patient 15 and the irradiation unit 2 .

The charged particle beam irradiation method further includes a step S10 of selecting an adjustment level according to the depth of the tumor 14 in the patient 15's body. In the step S30 of configuring the ventilator deenergizer 30, the selected ventilator deenergizer 30 may be configured. At this time, the ventilator deenergizer 30 can adjust the penumbra with an appropriate penumbra adjustment level according to the depth of the tumor 14 in the body of the patient 15 .

The charged particle beam irradiation method further includes step S10 of selecting an adjustment level according to the distance between the patient 15 and the irradiation part 2. In step S30 of configuring the ventilator deenergizer 30, the selected ventilator deenergizer 30 may be configured. At this time, the ventilator deenergizer 30 can adjust the penumbra with an appropriate penumbra adjustment level according to the distance between the patient 15 and the irradiation part 2 .

For example, as a comparative example, a charged particle beam irradiation system in which the snorkel deenergizer 30 is not provided at the front end portion 9 a of the irradiation unit 2 will be described. At this time, in the charged particle beam irradiation system, the energy of the charged particle beam B is controlled by an energy adjustment device (ESS: Energy Selection System) upstream of the beam transport path 21 . The energy conditioning device requires a large energy loss in the energy reducer 20 to change the reaching depth of the charged particle beam B in the patient's body. Therefore, the charged particle beam B has an expansion in the direction of motion. The energy adjustment device delivers a beam with expansion in the direction of motion, whereby as the charged particle beam B advances downstream of the beam delivery path 21, the beam size expands through drift and the penumbra also expands.

On the other hand, in the charged particle beam irradiation system 1 of this embodiment, the ventilator deenergizer 30 adjusts the penumbra of the charged particle beam B immediately in front of the patient 15 . Therefore, the energy loss in the energy reducer 20 on the upstream side is kept small and the energy loss used for the penumbra adjustment of the snorkel reducer 30 is increased, thereby making it possible to achieve a state in which the expansion of the beam size is suppressed. Irradiating patient 15 below can suppress the penumbra. Furthermore, since the thickness of the ventilator deenergizer 30 can be selected, the adjustment level of the penumbra of the ventilator deenergizer 30 can be appropriately adjusted according to the depth of the tumor 14 or the distance between the patient 15 and the irradiation unit 2 .

The present invention is not limited to the above-described embodiment.

For example, a snorkel deenergizer is illustrated as an adjustment member for adjusting the penumbra, but other members may be used as long as the penumbra can be adjusted. For example, a collimator or a multi-leaf collimator may be provided at the position of the holding part 60 , that is, immediately in front of the patient 15 , and the penumbra may be adjusted by the multi-leaf collimator. The multi-leaf collimator can adjust the penumbra by blocking the beam of the charged particle beam B at a position corresponding to the boundary portion of the tumor 14 . The adjustment level can be adjusted by the opening diameter. If the opening diameter is made larger (that is, a margin is provided in the outer diameter of the tumor), the penumbra will not be blocked. If the opening diameter is made smaller (fitting with the outer diameter of the tumor), the penumbra can be blocked. Penumbra. At this time, by adjusting the penumbra with the multi-leaf collimator at the position closest to the patient 15 (for example, 30 cm or less), the tumor 14 can be irradiated with the charged particle beam before the beam size of the charged particle beam B is enlarged. B.

The position where the holding part for holding the multi-leaf collimator is provided does not necessarily need to be the front end of the irradiation part, but may be the inside of the irradiation part.

1: Charged particle beam irradiation system 2:Irradiation part 14: Tumor (irradiated object) 15:Patient (object) 30: Snorkel energy reducer (adjusting component) 50:Scan electromagnet 60:Maintenance Department 80:Testing Department

[Fig. 1] is a schematic structural diagram showing a charged particle beam irradiation system according to an embodiment of the present invention. [Fig. 2] A schematic structural diagram of the vicinity of the irradiation part of the charged particle beam irradiation system of Fig. 1. [Fig. [Fig. 3] is a diagram showing the layers set for tumors. [Fig. 4] is a schematic diagram showing a state in which a snout deenergizer is held by a holding portion. [Fig. 5] is a graph showing the dose distribution when a charged particle beam is irradiated in a predetermined plane in which the scanning normal direction is at right angles to the base axis. [Fig. 6] is a graph showing simulation results related to the relationship between the spread of the charged particle beam and the depth of the target object. [Fig. 7] is a graph showing the simulation results when the thickness of the air layer is changed based on Fig. 6. [Fig. 8] is a graph showing the simulation results when the thickness of the air layer is changed based on Fig. 6. [Fig. 9] is a block diagram showing a structure for enabling selection of the adjustment level of the penumbra of the snorkel deenergizer. [Fig. 10] is a step diagram showing the contents of a charged particle beam irradiation method according to an embodiment of the present invention.

1: Charged particle beam irradiation system

2:Irradiation part

3:Accelerator

7:Control Department

8: Four-pole electromagnet

8a: Four-pole electromagnet in X-axis direction

8b: Y-axis direction four-pole electromagnet

9:Irradiation nozzle

9a: Front end

11: Profile monitor

12:Dose monitor

13a: Position monitor

13b: Position monitor

14: Tumor (irradiated object)

15:Patient (object)

20:Energy reducer

21: Beam delivery route

30: Snorkel energy reducer (adjusting component)

40:Collimator

50:Scan electromagnet

50A: Scanning electromagnet

50B: Scanning electromagnet

51:Collimator drive unit

60:Maintenance Department

90: Treatment planning device

95:Memory department

AX: base axis

B: Charged particle beam

Claims (5)

A charged particle beam irradiation system that irradiates a charged particle beam to an irradiated object in a target object. The charged particle beam irradiation system is provided with an irradiation unit that scans the charged particle beam with a scanning electromagnet to irradiate the irradiated object. irradiating the charged particle beam; an adjusting member that adjusts the penumbra of the scanned charged particle beam; and a holding portion that is provided on the irradiation portion and holds the adjusting member, and the adjusting member is configured to have a lower penumbra passing through it. The ventilator deenergizer for adjusting the energy of the charged particle beam can select the penumbra of the adjustment member according to the thickness of the ventilator deenergizer and the distance between the object and the irradiation part. Adjust levels. The charged particle beam irradiation system according to claim 1, wherein the holding part is provided at a front end of the irradiation part. The charged particle beam irradiation system according to claim 1 or claim 2, wherein the adjustment member has an adjustment level of the penumbra corresponding to the depth of the irradiated object in the object. The charged particle beam irradiation system according to Claim 1 or 2, wherein the adjustment level of the penumbra of the adjustment member can be selected based on the depth of the irradiated object within the object. Charged particle beam as claimed in claim 1 or claim 2 The irradiation system further includes a detection unit that detects that the adjustment member is incorrectly arranged with respect to the holding unit.

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